Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Emdrive Electromagnetic Drive For Chinese Space Ships?
Tired of those conventional space drives that require some sort of reaction mass? Chinese researchers claim to have confirmed the basic principles behind the Emdrive - an electromagnetic drive concept that converts electrical energy into thrust using microwaves.
The Chinese are currently building a demonstration model to see if it works.
('Emdrive' Electromagnetic Space Drive)
Take a look at the explanation offered on Roger Shawyer's Emdrive website:
The principle of operation is based on the well-known phenomenon of radiation pressure. This relies on Newton’s Second Law where force is defined as the rate of change of momentum. Thus an electromagnetic (EM) wave, travelling at the speed of light has a certain momentum which it will transfer to a reflector, resulting in a tiny force.If the same EM wave is travelling at a fraction of the speed of light, the rate of change of momentum, and hence force, is reduced by that fraction. The propagation velocity of an EM wave, and the resulting force it exerts, can be varied depending on the geometry of a waveguide within which it travels. This was demonstrated by work carried out in the 1950’s. (CULLEN, A.L. ‘Absolute Power Measurements at Microwave Frequencies’ IEE Proceedings Vol 99 Part 1V 1952 P.100)
Thus if the EM wave travelling in a tapered waveguide is bounced between two reflectors, with a large velocity difference at the reflector surfaces, the force difference will give a resultant thrust to the waveguide linking the two reflectors. If the reflectors are separated by a multiple of half the effective wavelength of the EM wave, this thrust will be multiplied by the Q of the resulting resonant cavity.
The inevitable objection raised, is that the apparently closed system produced by this arrangement cannot result in an output force, but will merely produce strain within the waveguide walls. However, this ignores Einstein’s Special Law of Relativity in which separate frames of reference have to be applied at velocities approaching the speed of light. Thus the system of EM wave and waveguide can be regarded as an open system, with the EM wave and the waveguide having separate frames of reference.
The beauty of engineering is that you can actually build something to test it; we'll find out soon enough if Emdrives will power space craft.
In the meantime, you might want to compare the Emdrive explanation with other famous pseudo-scientific science-fictional space drives. See the entries for the spindizzy from James Blish's Cities in Flight and of course the elegant infinite improbability drive from Douglas Adam's Hitchhiker's Guide to the Galaxy .
Via Wired; see also the Emdrive website.
Scroll down for more stories in the same category. (Story submitted 9/29/2008)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 5 )
Related News Stories - (" Space Tech ")
Beautiful Visualization of Dawn Spacecraft
'Then he became aware of a gentle pressure pushing him away from the ship.' - Isaac Asimov, 1939.
Tumblin' Tumbleweed Rovers To Eplore Mars
'His sensors out and working, and the whirring of the tape that sucked up sight and sound and shape and smell and form...' - Clifford Simak,
Tentacled Robot Captures Space Debris
Preventing annoying space debris build-up.
Reflect Orbital Sunlight On Demand
'I don't have to tell you about the seven two-mile-diameter orbital mirrors that circulate around the satellite, making it habitable.'
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
Warfare Goes Underground In Ukraine
'Once in the very first weeks of the war, before everyone had been evacuated from the surface...'
3D Printed Organs From Space
'For a while your colonists will have to come up to the [orbital] Hospital...'
Robot Bees 3D Printed By Festo
'At first I was struck by the large size of these bees..'
DIY Robot Scorpion Crushes It
'...it raised its front end off the ground and waved its antennae at them, then raised one armoured claw as if to snip them out of the sky.'
How To Settle An Argument Between Two Robots
'Henry... assumed the curious absent look of a robot talking on the TBR circuits.'
The Wind Phone Calls Those Who Have Passed On
'Only I heard that!'
Don't Want To Wear A TIght Shiny Bodysuit?
'He looked a good bit like an elderly, fat beetle.'
Light Society: Simulates Earth-Scale Society With A Billion AI Agents
'The king, an old hand in the running of tyrannies, instantly grasped the directions...'
Satyress Centaur Robot Horror Reminds Everyone Of Something
'Fess was very dutiful'
When Colds Threaten You Can't Do This - Or Can You?
'...a hemispherical force field enclosing his head.'
Beautiful Visualization of Dawn Spacecraft
'Then he became aware of a gentle pressure pushing him away from the ship.'
Biological War: A Scenario
'And now they wre busily transforming all their companions, and so on, and so on...'
Pole-Dancing Stripperbot Robot
'Why, a clockwork dancer, or, better still, one that would go by electricity and never run down...'
Collective Superintelligence Is At Hand!
'Maybe the individual intelligence of each Cubic pools into a group intelligence...'
Instant Journalists: Ordinary People With Cell Phones
'We'll show them whose planet this is!'
Health Kiosk Has No Human Doctor
'The electronic body analyzer had been developed...'
